Chlorophenoxyacetyloxazolidone herbicides and preparation thereof

ABSTRACT

3-(Chlorophenoxyacetyl)-2-oxazolidones are prepared by reacting a 2-oxazolidone with a chlorinated phenoxyacetyl chloride. When the oxazolidone is unsubstituted in the 5-position, presence of an acid acceptor is helpful to improve yield. The products are useful as herbicides.

United States Patent inventor Edwin D. Little Convent Station, NJ. Appl. No. 755,743 Filed Aug. 27, 1968 Patented Nov. 23, 1971 Assignee Allied Chemical Corporation New York, N.Y.

CHLOROPHENOXYACETYLOXAZOLIDONE HERBICIDES AND PREPARATION THEREOF 1 Claim, No Drawings 0.8. CI 260/307 C,

7 1/88 Int. Cl C07d 85/28 Field of Search 260/3073 [56] References Cited UNITED STATES PATENTS 3,221,021 l [/1965 Hickner 260/307 OTHER REFERENCES Morrison et al. Organic Chemistry 1959 Allyn & Bacon, Inc. p. 542

Primary Examiner-Nicholas S. Rizzo Assistant Examiner-R. V. Rush Anomeys-Patrick L. Henry and Fred L. Kelly CHLOROPHENOXYACETYLOXAZOLIDONE HERBICIDES AND PREPARATION THEREOF CROSS-REFERENCE TO RELATED APPLICATION This application discloses subject matter related to the invention of application of Edwin D. Little entitled Chlorophenoxyacetamide Herbicides and Preparation Thereof," U.S. application Ser. No. 755,747, filed Aug. 27, 1968.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The novel compounds of the instant invention are phenoxyacetyloxazolidones of the formula:

01-60 omii-qpcmorm wherein R is selected from the group consisting of hydrogen, alkyl containing up to six carbon atoms and alkenyl containing up to six carbon atoms; and R is alkyl containing up to three carbon atoms or chlorine. The products are useful herbicides.

The compounds are prepared by reacting a 2-oxazolidone with a chlorinated phenoxyacetyl chloride; when R is hydrogen, the presence of an acid acceptor in the reaction medium is preferred.

DETAILED DESCRIPTION OF THE INVENTION Preparation of the instant compounds is unexpectedly accomplished by reacting a 2-oxazolidone with a phenoxyacetyl chloride, according to the followingsequence:

wherein R and R are as aforesaid. Surprising, when R is hydrogen, it is preferred that an acid acceptor be present to obtain the desired product; when R is other than hydrogen, the reaction can be conducted satisfactorily without the presence of an acid acceptor.

Approximately equimolar amounts of the two substrates are used, although an excess of either might be used to achieve a higher yield with respect to the other.

The amount of acid acceptor which is preferably used when R is hydrogen is sufiicient to neutralize the full amount of hydrogen chloride which is coproduced, i.e., an amount equivalent to the theoretical amount of hydrogen chloride to be formed. Most preferably, the reaction will be conducted at a pH greater than about 7.0 when R is hydrogen.

Acid acceptors which are suitable for the instant reaction include amines such as pyridine, triethylamine and tribu' tylamine. Also, inorganic bases such as sodium hydroxide might be used. Triethylamine is the preferred base.

The reaction may be conducted in an inert solvent although it is more convenient not to use solvent. For this purpose, the reaction is conducted above the melting point of the oxazolidone, e.g., above about 89 C. for 2-oxazolidone itself. Generally, the temperature will be between the melting point of the oxazolidone and 150 C. Reaction times as short as about I hour or less have been found to be adequate, although longer reaction times may be used if desired.

Atmospheric pressure is normally used for the reaction, although subatmospheric conditions may be used if desired.

The reaction might be conducted in an inert solvent, if desired, such as chloroform or carbontetrachloride or in a solvent amount of liquid base, such as triethylamine or tributylamine. Conditions regarding reaction temperature, time and pressure s'pecifled hereinbefore are appropriate for this purpose. although somewhat lower temperatures might be used if desired.

Substrate materials are readily available by procedures taught in the prior art. For example, 2-oxazolidones might be prepared by heating tris( Z-hydroxyalkyl)isocyanurates or tris(2-hydroxyalkenyl)isocyanurates to l50250 C. in the manner taught by US. Pat. No. 3,108,115, and the various phenoxyacetyl chlorides are available by treating the corresponding phenoxyacetic acid with thionyl chloride, which acid is in turn prepared by reacting the corresponding phenol with monochloroacetic acid.

The instant compounds have been found to be unexpectedly effective herbicides in that they are very harmful to plants normally considered undesirable, such as rape and broad-leafed weeds, while being harmless toward such plants as soybeans, corn, wheat, and cotton. Preferred compounds are 3-(2,4- dichlorophenoxyacetyl)-5-methyloxazolidone-2 (R' is chlorine, R is methyl); 3-(4-chloro-2-methylphenoxyacetyl)- 5-methyloxazolidone-2 (R' and R are methyl); 3-(2,4- dichlorophenoxyacetyl)oxazolidone-2 (R' is chlorine, R is hydrogen); and 3-(4-chloro-2-methylphenoxyacetyl)-5- vinyloxazolidone-Z (R' is methyl, R is vinyl).

Normally the instant compounds will be used as the active ingredient in an herbicidal composition, although they might also be used without a carrier. Various diluents and carriers may be employed and the percent of active ingredient may be varied. Although compositions with less than about 0.5 percent by weight of active ingredient may be used, it is preferably to use compositions containing at least about 1.0 percent of active ingredient because otherwise the amount of carrier becomes excessively large. Activity increases with the concentration of active ingredient, which may be l0, 50, percent or even higher.

The amount of composition which is applied for effective herbicidal action is dependent upon considerations such as the type of undesirable plant to be killed, the density of undesirable plants, and soil and climatic conditions. Usually, sufficient composition will be applied to provide about 2-16 pounds of active ingredient per acre.

The instant herbicidal compositions may be in the form of a solution, with the solvent being selected from acetone, benzene, petroleum fractions and the like. These solutions can be applied to the plants in a direct mariner such as by spraying, sprinkling, drenching, etc. Water suspensions can also be applied in this manner, with dispersing and emulsifying agents such as sodium alkyl sulfates and sulfonates and the like.

Application can also be achieved by dusting a powder in which the active ingredient is dispersed. Suitable carriers include finely powdered material such as clay, fullers earth, talc, etc.

The instant compounds may constitute the sole active ingredient in the herbicidal compositions, but they might be effectively used in combination with other active ingredients, such as other herbicides, insecticides and other plant treating agents.

The following examples are provided to more fully illustrate the instant invention. They are provided for illustrative purposes only and are not to be construed as limiting the scope of the instant invention, which is defined by the appended claims.

EXAMPLE 1 3-( 4-Chloro-2-methylphenoxyacetyl )-5-methyloxazolidone-2 5-Methyloxazolidone-2(l0 g., 0.1 mole) was heated to about 100 C. over a steam bath and (4-chloro-2- methylphenoxy)-acetyl chloride (22 g., 0.1 mole) was added thereto. Heating was continued for an additional 30 minutes, after which time the reaction mixture was poured onto ice water. The precipitated solid was collected by filtration, washed twice with water, and then recrystallized from hot acetone. The resulting material, 14.5 g. (5 l%), m.p. l l7l22 C., was recrystallized from absolute alcohol to afford the desired product, 13 g. (46%), mp. 125 C.

Anal. Calcd. for C l-l ClNO C, 55.0; H, 4.94; N, 4.94. Found: C, 54.80; H, 5.02; N, 5.18.

EXAMPLE ll The procedure of example i was repeated using appropriately substituted oxazolidones and phenoxyacetyl chlorides to afford the following compounds:

3-(2,4-dichlorophenoxyacetyl)-5-methyloxazolidone-2 3-( 2,4-dichlorophenoxyacetyl )-5-vinyloxazolidone-2 3-(4-chloro-2-methylphenoxyacetyl)5-vinyloxazolidone-2 EXAMPLE Ill The procedure of example i is repeated using appropriately substituted oxazolidones and phenoxyacetyl chlorides to afford the following compounds:

3-( 2,4-dichlorophenoxyacetyl )-5-isopropyloxazolidone-2 3-( 2,4-dichlorophenoxyacetyl )-5-n-hexyloxazolidone-2 3-( 2,4-dichlorophenoxyacetyl)-5-allyloxazolidone-2 EXAM PLE IV 3 5 3-( 2,4-Dichlorophenoxyacetal )oxazolidone-2 2-Oxazolidone (8.5 g., 0.097 mole) was melted over a steam bath, and to the fused material was added 2,4- dichlorophenoxyacetyl chloride (24 g., 0.1 mole). The mixture was heated over the steam bath for an additional 30 minutes, after which time it was mixed with ice water. The resulting precipitate was separated by filtration, washed with 2 portions of water and then thoroughly mixed with water in a blender and separated again by filtration. The solids were placed in hot alcohol and the insoluble material was separated by filtering the hot mixture. The separated solids were dried to afford the desired product, 5.0 g. (17.7%), m.p. l70-l 7 1C.

EXAMPLE V The procedure of example I! was repeated wherein triethylamine l0.l g., 0.1 mole) was added to the initial melt of 2-oxazolidone, resulting in the formation of 3-(2,4- dichlorophenoxyacetyl)oxazolidone-2 product in improved yield.

EXAMPLE Vl Herbicidal Activity Each flat received a volume of spray equal to gallons per acre of an acetone solution of the herbicide. The concentration of the solution was adjusted to provide application of 2,4 and 16 pounds of active ingredient per acre. Immediately after spraying, the test flats were placed in aluminum trays and were irrigated until the surface of the soil in the flat was uniformly moist (at field capacity). Additional subirrigation was provided as needed to maintain moisture. No surface irrigation was applied.

The flats were sprayed within one day after seeding in preemergence tests, and 8-10 days after seeding in the postemergence tests. Results were observed 14 days after spraying.

The effect of the herbicide was evaluated in terms of the injury rating index scale, ranging from O to 10 as follows:

0-No apparent injury LLB-Slight injury 4,5,6-Muderate injury 7,8,9-Sevcrc injury (plants will die) lO-Plants were dead. An injury rating of 3 is the maximum tolerated for crops and a rating of 7 is the minimum acceptable on weed plants.

* l6 pounds of active ingredient per acre. "4 pounds of active ingredient per acre. "2 pounds of active ingredient per acre.

i. E?-l-wa yln lsn s3 lii zs'lu ee liwsi..-

lnjury rating Plant Prcemcrgcncc Pustemergence e e e e o o e e e e e 0 Corn l 0 0 2 1 0 Wheat l 0 0 0 0 0 Cotton 0 0 0 l0 l0 l0 Soyhcuns 3 0 0 l0 l0 l0 Ryegruss 0 0 0 0 0 0 Rape 9 7 5 l0 l0 l0 Crahgrass 9 7 5 Not tested l6 pounds of active ingredient per acre. "4 pounds of active ingredient per acre. "2 pounds of active ingredient per acre.

3-(2 ,4-Dichlorophenoxyacetyl)oxazolidone-2 lnjury rating Preemergence Postemergence Plant Not tested "l6 pounds of active ingredient per acre. "4 pounds of active ingredient per acre, "'2 pounds of active ingredient per acre.

3-( 4-Chloro-2-methylphcnoiiyacetyl )S-vinyloxazolidone-Z Flam Injury rating Preemergence Poslemergencc Canon Rape 9 9 9 l l0 l0 Crabgrass 9 N0! lasted 16 pounds of active ingredient per acre. "4 pounds of active ingredient per acre. "*2 pounds of active ingredient per acre.

PO-IOSO Patent No.

Inventor(s) EDWIN D. LITTLE Dated Ngygmber 2;. 1,211

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I Column 4, beginning at line 58, through the end of the specification ending at column 6, line 6, should read as follows:

3-(g, l-Dichlorophcnoxyacetyl)oxazo1idone-2 Injury rating Plant Preemergence rostemergence 1"! iii i iiiii Corn 2 0 O 2 0 Wheat Q o o o 0 Cotton 3 o 10' 9 9.5

'Soybeans 0 0 1O 9 7 Ryegrass 0 O O r O O Rape 9 10 9 9-5 Crabgrass 7 Not tested 16 pounds of active ingredient per acre I pounds of active ingredient per acre '2 Qounds of active ingredient per acre B-(H-Chloro-2-methylphetxoxyacetyl )-5-vinyloxa2olidone-2 Injury r a tins; Plant Preemorgence rcstemergence I 'II' If! *-I- l Corn l 2 1 0 O 0 Wheat 5 o o o 3 3 Cotton 2 O 3 10 10 1O Soybeans 2 0 0 10 9 9 Ryegrasa 5 2 2 O 0 x Rape 9 9 9 1O 1O 1O ;C rnbgrass 9 Not tested- 16 pounds of active ingredient oer acre 4 I l pounds of active ingredient per acre pounds 01 active ingredient per acre Signed and sealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD M.FLE1CI-IER, JR.

Attesting Officer ROBERT GOTTSCHALK Commissioner of Patents 

